About High Pressure Processing (HPP)

Why did Rad Cat decide to HPP their poultry and venison?


At Rad Cat, we have always taken food safety very seriously.  We produce in our own facility, where we follow the strictest food safety guidelines and we carefully source all of our ingredients.  We strive to continuously improve and enhance the safety of our products and look ahead to comply with future regulations.  The Food Safety Modernization Act is requiring all manufacturers of ‘ready-to-eat’ foods, including raw pet food, to apply intervention methods to ensure food is pathogen-free.  While we truly believe that most bacteria that are present in raw diets are harmless to our cats, we must be compliant with the upcoming requirements. 


Poultry is the biggest concern for the FDA, namely for salmonella, but also for Listeria monocytogenese and for E.coli O157:H7.  HPP has been demonstrated to inactivate these bacteria, while still maintaining the nutritional integrity of the raw materials.


We are not HPP-ing our finished product – only the poultry dark meat and organs that we use in our recipes, which is the greatest concern for our regulatory bodies.


Our recipe has not changed, our sourcing has not changed.  We still use organic chicken in our Chicken variety and we use free-range turkey in our Turkey variety.


The FDA and USDA tolerate a certain number pathogens (such as salmonella and listeria) in meats and poultry that are intended for human consumption.  However, there is a zero tolerance for raw pet food.



What is HPP?


There is considerable mis-information about HPP, published by others in the pet industry, which we will address in the FAQ’s to follow.


HPP is a very simple process that uses water pressure, at pressures up to 87,000 psi, to destroy bacteria, such as salmonella, listeria and E. coli. It is often referred to as “cold pasteurization” and is a completely heat-free process.  Pressure is applied throughout the poultry, where it essentially “cracks” the protective outer covering of some bacteria, leaving them to “succumb” to their environment.


It is recognized by the USDA and FDA as an anti-pathogen treatment or “kill step” for many food products.  HPP is also approved for organically labelled products.


It is the only FDA-recognized process that does not involve heat or irradiation to kill harmful bacteria.




Doesn’t HPP kill good bacteria? 


No it doesn’t - not in meat. Raw meat does not contain probiotics or ‘beneficial bacteria’ - the only exception being tripe. There are many studies that discuss how HPP will kill good and bad bacteria, but after years of research, we have never come across any research that supports that there are ‘good’ bacteria' present in raw, animal muscle tissue, such as a chicken or turkey thigh. There are spoilage organisms, non-pathogenic bacteria and pathogenic bacteria (such as salmonella) that are present on the surface of the meat with none of them being "beneficial".  There are beneficial enzymes present in muscle tissue, but we have found no research supporting claims of beneficial bacteria being present in striated muscle tissues of animals.  



I hear HPP’d food isn’t raw any more. . . doesn’t it change the proteins?


There are many arguments about whether raw, HPP’d food is still raw.  Yes, we believe it is still raw.  It is not exposed to high temperatures and the proteins are not ‘denatured’ like they are in cooking.


First let’s talk about ‘denaturing’.  This term is very loosely used in the industry.  “Denaturing”, in purely scientific terms, refers to the alteration of a protein’s structure, whether by heat, chemical reaction (like how seafood is “cooked” in ceviche), enzymes, agitation (like whisking egg whites) or even salt. And, the extent of denaturation really depends on what is being HPP’d.  HPP changes the structure of a few proteins (not all of them), namely the ones that have to do with color and texture.  For example, ferrous myoglobin is responsible for the red or pink color of meat.  HPP causes the ferritin to oxidize, yielding ferric metmyoglobin. This oxidation  is the same reason why meats at the grocery store that are not ‘treated’ with CO2 turn brown in the meat case.  It is a natural process and does not change the nutritional quality of the meat.


Most proteins in meats, poultry and fish are called ‘fibrous’ proteins.  These react very differently to HPP than “globular” proteins that are present in vegetables, eggs and dairy. There are some globular proteins in meat and poultry, but nowhere near the quantities in other foods.  There is some mis-information published about HPP that is referring to studies done on how HPP affects these "globular" proteins (to create gels, etc.), but these studies were done on soy and other plant products.  The proteins in soy, dairy and other vegetables are vastly different than those found in fresh, raw meat. They have different structures and react differently to pressure.


Meats that are treated or ‘rinsed’ with antimicrobial solutions, such as peracetic acid, lactic acid and citric acid, also run the risk of protein denaturation.  We have chosen to use HPP, rather than run our poultry through these rinses or dips, as it is the most reliable in eliminating pathogens.


Please note:  The ‘denaturation’ we are referring to is different than what some folks refer to as ‘denatured meat for pet food’.  Meat that is ‘denatured for pet food’ is meat that is not intended for human consumption and is treated with a chemical that turns the meat green – so that it can be visually distinguished from meat that is intended for human consumption.  This meat is NOT what we use or will ever use.  We only use meats that are intended for sale in the retail, grocery market – for humans.  The other ‘green stuff’ goes into other pet foods, such as in some dry and canned, as it is meant to be cooked (further denatured).


Does HPP affect enzymes?


HPP has a VERY limited effect on some enzymes. This is determined by holding time at pressure and if there is heat applied.  The beneficial enzymes in Rad Cat are still present, in their natural state.  Many studies that talk about HPP’s effects on enzymes refer to changes in protein structures under high pressure, high temperature (heat) application AND extended time under pressure, such as 5, 30 and even 60 minutes.  The holding time for Rad Cat’s poultry is 180 seconds, which is a vastly different holding time than studies that opponents to HPP are citing.  


 HPP is not sterilization!


HPP only affects certain bacteria – not all.  There are still non-pathogenic organisms that are naturally present in all raw meats (and also produce and any other food product).  These are harmless spoilage organisms that will still proliferate over time.


The term ‘sterilization’ is a term that has been used to describe the HPP process, but is not at all accurate.  HPP does not sterilize food products.  The term ‘sterilization’ is defined as ‘a process that removes all forms of life or biological pathogens, such as viruses’.  HPP does not do this.  If this were to be true, running an Aerobic Plate Count analysis would show zero bacteria present.  As there are still harmless spoilage organisms present in any food, the APC will still yield a positive value.  It will reduce spoilage organisms, which is why produce, and ready-to-eat food manufacturers such as those that produce hummus, guacamole, etc. use HPP to extend shelf life. 


What about spores?


The only reason we are addressing this is because there is some information published about HPP not killing bacterial spores in raw meat.  There is only one pathogenic bacteria that is likely to be present in raw meat that can form spores, and that’s Clostridium species, such as perfringens.  E.coli, salmonella and listeria are not spore forming bacteria.  Clostridium spores will only be present if the bacteria is found in very large quantities, which is HIGHLY unlikely in humanely-raised, well-cared-for flocks and herds.  These are the farms we source from.


If farm animals have a Clostridium infection, it will be evident, as they will exhibit symptoms and will appear ill.  These animals may be administered drugs or be euthanized, but they will not be used in Rad Cat products.  The poultry and meat in Rad Cat products come from animals that do not live in crowded environments, are very well monitored and cared for and eat healthy diets – all of which are preventive controls for Clostridium species.